B2338 — Mirror Switch Assembly Circuit Short to Battery #

Note: The description of code B2338 can vary depending on the vehicle manufacturer.

• Mirror Switch Assembly Circuit Short to Battery (Ford, Lincoln, Mercury)
• Power Mirror Switch Circuit High (GM/Chevrolet)
• Mirror Control Switch Circuit Short to B+ (Dodge, Chrysler, Jeep)

Summary of Code B2338 #

Diagnostic Trouble Code (DTC) B2338 indicates that the vehicle’s Body Control Module (BCM), sometimes called the Smart Junction Box or General Module, has detected an electrical short to battery voltage in the mirror switch assembly circuit. This means the circuit controlling the mirror adjustment switch is receiving higher voltage than expected, likely due to unintended contact with the battery positive voltage. While this code is not as common as engine-related DTCs, it can cause issues with mirror functionality and may suggest an underlying electrical problem in the door harness or switch assembly. Addressing this code promptly helps prevent additional electrical faults and ensures safe operation of the vehicle’s power mirror system.

Common Symptoms for Code B2338 #

Drivers or technicians may notice several issues related to the power mirror controls when code B2338 is present. The severity can range from minor inconvenience to total loss of mirror adjustment. Here are typical symptoms:

• Power mirrors do not respond to switch inputs
• Mirrors move on their own without input
• Intermittent or erratic mirror movement
• Mirror switch feels warm or hot to the touch
• Blown fuse related to mirror or door electronics
• Warning lights or messages about mirror adjustment system (on some models)

Likely Causes of Code B2338 (in order of frequency) #

The root cause of a B2338 code can be traced to electrical issues, physical damage, or internal switch failures. Based on repair data and typical vehicle design, here are the most common causes, ranked by frequency:

1. Damaged or pinched wiring harness in the door or between door and body (especially at the hinge area)
2. Faulty mirror switch assembly (internal short circuit)
3. Corrosion or water intrusion in the door connector or switch
4. Incorrect aftermarket wiring (e.g., alarm or audio install tapping into mirror circuit)
5. Defective Body Control Module (rare)

Step-by-Step Diagnostic Procedure for B2338 #

A systematic approach is critical to avoid unnecessary part replacement and ensure the root cause is fixed. Here’s a stepwise diagnostic routine:

1. Verify the code with an OBD-II/EOBD scanner and clear any stored codes to see if it returns immediately.
2. Test power mirror operation from the inside switch—note which functions (left, right, up, down) are affected.
3. Inspect the wiring harness in the driver’s door jamb for signs of rubbing, pinching, or broken insulation.
4. Disconnect the mirror switch assembly and check if the code clears or changes state.
5. Check for voltage at the mirror switch connector (with the switch unplugged). Battery voltage on any signal or ground wire means a short to power.
6. Visually inspect the switch assembly for signs of overheating, corrosion, or water damage.
7. If all wiring and switch tests pass, check the BCM or related control module for proper output and any signs of internal failure.

Possible Repairs for Code B2338 #

Repair options will depend on which fault is found during diagnosis. Always confirm the repair by clearing the code and retesting the system:

• Repair or replace damaged wiring or connectors in the door harness
• Replace the mirror switch assembly if internal short is confirmed
• Clean or replace corroded or water-damaged connectors
• Remove or correct improper aftermarket wiring (restore OEM configuration)
• If verified, replace the Body Control Module (rare)

Is It Safe to Drive with Code B2338? #

Usually, yes—but with limitations. Code B2338 typically does not affect engine or driving performance. However, if the mirrors are stuck in an unsafe position or move unexpectedly while driving, visibility can be compromised. Also, if the short causes repeated fuse failures or other electronics to malfunction, this might distract the driver or affect other systems. Best practice: Address the fault as soon as possible, especially before long trips or if you rely heavily on power mirror adjustments for safe lane changes.

Vehicles Most Commonly Affected by Code B2338 #

Based on technical service bulletins and repair frequency, B2338 most often appears on:

• Ford F-Series trucks (F-150, F-250, etc.)
• Ford Explorer, Expedition, Taurus
• Lincoln Navigator, Town Car
• Mercury Mountaineer
• Chevrolet Silverado and GMC Sierra (as Power Mirror Circuit High)
• Dodge Ram (as Mirror Control Switch Circuit Short to B+)

However, any vehicle with power mirrors and electronic controls can potentially experience this code.

Common Mistakes & Best Practices for B2338 #

It’s easy to misdiagnose electrical issues like B2338, especially if you skip steps or replace parts without testing. Here’s what to avoid—and what to do instead:

• Mistake: Replacing the mirror switch without inspecting wiring—Always check door harness first.
• Mistake: Overlooking corrosion or water intrusion at connectors.
• Mistake: Ignoring aftermarket alarm/audio wiring spliced into the mirror circuit.
• Best Practice: Use a wiring diagram specific to your vehicle and check all related fuses.
• Best Practice: After repair, operate all mirror functions and check for returning codes before returning the vehicle to service.

Quick FAQ for Code B2338 #

Q: Can a bad mirror motor cause code B2338?
A: Not directly. B2338 relates specifically to the switch circuit, not the motor. However, a shorted motor could potentially affect wiring, so always check the entire circuit if in doubt.

Q: Will disconnecting the battery clear this code?
A: Disconnecting the battery may clear the code temporarily, but if the underlying short exists, the code will return as soon as the circuit is powered again.